The D2a Diesel with never changing fuel economy

**OffTrack** · 17th April 2012, 09:19 PM

Just so we don't go thru the exercise of getting twr7cx to repeat what has already been tried, this is a post from the previous owner (DiscoWhite) made in October 2010:

not happy jan!
i cant stop my D2a using diesel like a funnel
a tank is only worth 450klm to me round town, hwy or towing.
over the past 12months its gotten worse, was 550klm/tank..
and i also still cant get rid of the 730-810rpm engine miss/dip at idle.
this is the same for the factory ecu mapping and a BAS tune.

so far ive replaced...
MAF, OEM
CAS, OEM installed with and with out the spacer
MAP, OEM
AAP, x2 both OEM, 1 from a working TD5 and 1 from a wreck.
BOOST MODULATOR, OEM even tried it bypassed.
INJECTOR HARNESS, OEM modified for oil ingression.
second set of known ''good'' injectors. (yes coded with nanocom)
NEW OEM ECU (no oil at ecu plug or in old ecu.)(security done with nanocom)
the head has just been skimmed .006'' and the valves re seated due to broken plastic head dowls
i had compression of 240-260psi per cylinder (TD5 i tested was 320psi)
tomorrow i will do another compression test and compare.
piston protrusion was on average .505mm = 1 hole gasket(same as original)
the head had its ports cleaned up, not quite match ported as did the turbo flange's.
the exhaust manifold has had the webs removed and been machined.
now im getting over boost, im hitting 1.40bar.... ive adjusted the rod out so much its a dog to drive under 60kph.
ive also fitted a known ''good'' turbo and wastegate actuator.
and still the problems remain...
the timings correct and the injector preload is too.
its not using/making oil or water.
fuel pressure is 4.0-4.3bar.
before the head was done my oil test showed 5% diesel dilution and a high reading of sillica (ultra blue gasket was used previously)

i have a good TD5 in the drive way to compare with and all the figures and values shown by nanocom are 99% the same D2 to D2!
both auto, both modified simmilar. mine has 255 70 R16's the other has 235 85 R16's 30 000 k's differance in odo readings, both EU3 motors. the other got 836klm to the low fuel light last tank.

my auto fluid and filter was done 5000k's ago, still looks clean dosnt smell burnt and there are no visible particles in the oil. the auto ecu has also been changed!!!
mine dosnt shift as well as as the other, mine hangs in first a little to long and can hesitate on shifts. ZF australia wont return my phone calls or answer my emails... great customer service...******...
and the other 2 auto shops tell me it cant be tested??? WTF..

so apart from replacing the speed sensor in the auto and the coolant temp sensor...there isnt too much i havnt done.

so if ANYone has ANY ideas im hear waiting for your input.

oh and the drive train has been looked at, ie, brakes dragging, bearings, tail shaft etc...all perfect.

**strangy** · 18th April 2012, 07:12 AM

Thought there was an apparent resolution to this with a replacement fuel reg.
Seems not.

**OffTrack** · 18th April 2012, 07:16 AM

Originally Posted by strangy

Thought there was an apparent resolution to this with a replacement fuel reg.
Seems not.

Apparently not. I'm wondering if it might be something like a fuel temp sensor, hence the recording of ECU inputs.

**strangy** · 18th April 2012, 11:09 AM

I recommend a borrowed STD ECU afm and return the rig to STD for testing. The IC won't matter.
There is no start datum for you to troubleshoot from. I think "off track" is on the right path with the ECU.

Too much time wasted chasing the issue from an unknown baseline. Returning to STD is quick and easy. If the car has poor fuel usage STD, then you can rule out all your mods and start on things like timing, engine condition, drive train issues.

With respect, don't assume anything about this car anymore and start back at the basics that YOU have checked and confirmed correct and ignore what others claim has been checked and "done"
Sound knowledge, capability and appropriate tools are obviously necessary for the fix.

From all of your posts, and making many assumptions,I would say your ECU map is the culprit or your motor is stuffed.
Cheers

**OffTrack** · 18th April 2012, 01:11 PM

Strangy,

While I agree back to basics is a good idea, I don't think we should ignore the work DiscoWhite did 18 months ago trying got solve the same problem on the same D2.

my D2a TD5 is a pile of dog poo!

The question that springs to mind is whether the ECU and stock map that the remap was built on are correct for the motor/gearbox combo.

cheers
Paul

Add:

my D2a TD5 is a pile of dog poo!

In chasing an idle problem it appears there was an early version of the NNN map installed. This was done on JustinC's advice, and I'd be hesitant to write off his wisdom.

**strangy** · 18th April 2012, 05:43 PM

I have read all of the posts previous including Disco Whites.
I doubt JC or DW would take it personally if their ECU/Map was responsible. I reckon they would be happy to know the issue and help sort it.
Yet frankly I would be surprised if it was the fuel map given that this is the 3rd for this rig? Furthermore the maps are not likely to be "one offs" therfore others would have complained too. However this does not rule out the map or ECU itself.

10 mins work to substitute a known working ECU from the appropriate model and a few weeks testing with a bit less grunt sure beats expensive trial and error component swaps. Providing a definitive starting point.
But if twrc7x wants to continue down another path thats his choice.
Its basic fault finding 101.

cheers

**twr7cx** · 25th April 2012, 11:38 AM

I still need to record the ECU inputs.

However, I spoke to Kelvin ( disco_thrasher ) about the tune he fitted for the previous owner and got the following response:

Hey Scott
sorry about delayed reply as i work in the mines offshore and just got back ,I stopped the been the franchise in oz about 13 mnths ago due to my work commitments you can try contact td5 INSIDE The ultimate solutions for remapping TD5´s direct Jose is his name ,but i recall Phill wanted power and speed out of his tune so it was designed for that so to get a new tune would be buy a tamned down tune
Kelvin
d

Today I found a nice private piece of straight road and booted the vehicle while looking backwards. The smoke out the back is thick and very black. The vehicle is clearly running far too rich which explains the high fuel consumption and possibly would cause higher temperatures (as I think diesels are backwards - lean runs cool, rich hot). Also I'm not convinced I would be getting the best performance out of an engine running so rich.

**Milkman Dan** · 25th April 2012, 11:20 PM

Black smoke is unburnt fuel, not enough air is getting in to burn it all.
There should be no smoke, either cut back on the fuel going in or boost the air.

**twr7cx** · 26th April 2012, 07:37 PM

Originally Posted by Milkman Dan

Black smoke is unburnt fuel, not enough air is getting in to burn it all.

Yes, correct. This is often called running rich - hence my statement above that the motor is running far too rich.

Originally Posted by Milkman Dan

There should be no smoke, either cut back on the fuel going in or boost the air.

Increasing air isn't an option. Already running at 20psi, which is the limit for reliability. Going to fit the VNT, but I'm not sure it'll have too much effect.

Cutting fuel is the way to go, but that seems like it's going to require a retune at the ridiculous cost...

**twr7cx** · 30th April 2012, 09:36 PM

td5inside has offered to provide an improved map to suit the soon-to-be-installed VNT turbo at no cost. Hopefully this may help to reduce the running rich condition.

Thread: The D2a Diesel with never changing fuel economy

Thread Tools

Bookmarks

Bookmarks

Posting Permissions